Lumber-joint.



UNITED STATES PATENT OEEICE.

MATTHIAS B. EATON, OF BOSTON, MASSACHUSETTS.

.LUMBER-JOINT.

SPECIFICATION forming part of Letters Patent No. 671,954, dated April16, 1901.

Application filed July 21| 1900.

To all whom it may concern:

Be it known that I, MATTHIAS B. EATON, a citizen of the United States,residing at Boston, in the county of Suffolk, and State of Massachusetts,have invented certain new and useful Improvements inLumber-Joints.; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled inthe art to which it appertains to make and use thesame. j

My invention relates to improvements in lumber-joints; and it consistsin a new'and improved method of constructing a tongueand-grooved joint,whereby the joint can be made to fit more closely and .to be less liableto injury in handling, especially lesseing the liability of breaking thetongue and the sides of the groove. It also makes a good lockjoint.

In the drawing a transverse section of boards joined together is shownto illustrate my invention.

In said drawing, A represents boards provided with tongues and grooves.The groove is formed in the edge of one board and the tongue on the edgeof another board, exceptwhen the boards are to be joined togetherangularly,`in which case the groove will be made in the face of theboard; The groove starts in the edge of the board at a suitable distanceD from the side and extends into the board in a direction inclinedoutwardly and near the bottom of the groove terminates in a curve Einstead of an angle. On the opposite side it begins a suitable distanceF from the side of the board, extends inwardly a short distance G,thence curving into a substantially transverse direction H, and thenceinto a substantially parallel direction I, terminating in a curve .I atthe bottom, thus forming a groove deeper on one side than on the other.This arrangement of the outlines of the groove obviates all right anglesand lessens very materially the tendency to break at the apeXes of theangles, the ordinary tongue and groove being especially weak at thesepoints. The tongue is made on lines the reverse of those of the grooveand is adapted to completely ll the groove in the opposite member andSerial No. 24,348. (No model.)

make a close joint. It is consequently at the base considerably widerthan at the end. The widest portion of the tongue on one side bears onthe raised portion of the bottom of the groove, raising the point ofleverage above the bottom of the groove, thereby lessening the tendencyto break the tongue. This arrangement is also advantageous in affordinga stronger hold for the .nail which holds the boards together. Nails Kare driven through the sides of the groove into the tongue from one sideinto the long side of the tongue and from the other side into theopposite side of the tongue.

To make the joint lock, I curve the longv side of the groove outwardly,as seen at X, and make a corresponding bulge Y on the long side of thetongue. This construction prevents the two from drawing out of thegroove in a direction parallel with the sides of the boards and makes awater and air tight joint. The edges of the board on different sides ofthe tongue or groove are not in the same line, as seen at O and P. Thisenables the bulging portion of the tongue to be more readily inserted inthe groove and renders the tongue less liable to be broken.

Having thus described my invention and its use, I claim- 1. In alumber-joint, one member having a tongue with an offset on one side andwith one or more steps on the other side and a second member having agroove adapted to receive and conform closely to the surfaces of saidtongue.

2. In alumber-joint, one member having a tongue with an offset on oneside and one or more steps on the other side, said tongue being boundedby a series of convex and concave surfaces, and a second 'member havinga groove adapted to receive and conform closely to the surfaces of saidtongue.

In testimony whereof I affix my signature, in presence of two witnesses,this 16th day of June, 1900.

MATTHIAS B. EATON.

Witnesses:

J. H. RUSSELL, J. S. KETCHAM.

